I accidentaly left default settings for my animation and hit render. After it rendered out I couldnt find the output image sequence. It said that they are outputed in /tmp/ but there is no images/videos in /tmp/ folder I cant add it to video edditor because I dont know where the image strip is....
To render an animation, you need to click the 'Animation' button shown below. And to see the location of those renders click on the folder icon marked with red box in the below image. Once you click that icon, it will show you the exact path in the top portion of the screen.
From the Linux Filesystem Heiarchy documentation:
people and programs must not assume that any files or directories in /tmp are preserved between invocations of the program
The exact operation of your distribution is subject to it's own configuration, however if you have restarted your operating system between rendering and looking for the files, I would be less than optimistic that those files still exist.
In order to avoid this issue, please refer to @Teja's answer.
You can notice that the Blender only save the png sequence or the video if you hit Animation.
If you hit Render it will render only one frame and wait for you to save it.
I made a test and the tmp folder stores the files as intended to do.
As you said: You hit Render but you did not saved that render image. Then, there is nothing on the tmp folder.
See the image below: